The present invention relates to an apparatus and a method for making antennas for radio-frequency identifying devices, commonly know as RFID transponders, provided with antennas formed of an electrically conductive wire, or of a braid of flexible wires, for example copper.
The term “flexible” is defined as a wire, or a braid of wires, that cannot maintain a stable configuration without being kept tensioned or without being fixed to a surface.
RFID transponders include two essential parts, the aforesaid antenna, made of electrically conductive material and an integrated circuit or microchip connected to the two ends of the antenna.
Making the antenna with a thin flexible wire made of electrically conductive material is known, for example a copper wire that is no more than 150 μm in diameter, connecting the ends to a module, also called a strap or interposer, which includes the integrated circuit or microchip.
Welding is necessary for HF band transponders whereas for UHF transponders the use of an antenna loop is known that includes the short range or near field integrated circuit that is readable at a close distance, to which a second antenna is added in the vicinity without a connection. The second antenna is coupled inductively with the integrated circuit to form a transponder operating long range or far field.